1. Field of the Invention
Embodiments of the present invention relate to an apparatus and method for closing or opening an opening, especially a bottom opening of a material hopper for a blast furnace, and a blast furnace having such an apparatus.
2. Description of Related Art
DE 103 27 276 A1, for example, discloses an apparatus including a shut-off flap valve or furnace mouth flap valve, which is used to control the charging of a blast furnace with coke and burden material. For the purpose, the apparatus includes a flap plate which, for the purpose of closing or opening the bottom opening of a material hopper arranged above the mouth of a blast furnace, is movable into an open position and into a closed position. In order to move the flap plate into the desired position, a drive mechanism is usually in articulated connection at the flap rim, by which it is ensured that, in the open position, the flap plate leaves the flow opening substantially completely clear. In the process, however, the flap plate is pivoted out relatively far away from the opening, so that the mouth of the blast furnace has to be correspondingly dimensioned in order to avoid a collision of the flap plate with loose material.
In the case of the furnace mouth flap valve according to DE 103 27 276 A1, this disadvantage is avoided by the fact that the flap plate is in articulated connection with two pivot arms which are mounted so that they can pivot about pivot axes that extend parallel to one another. It is ensured therein that, when the flap plate moves from the closed position into the open position and vice-versa, the rim regions of the flap plate move along oppositely directed arcuate paths. The multiply superimposed tilting/translational movement of the flap plate obtained in that manner brings about a movement of the flap plate on a trajectory close to the bottom opening, as a result of which the mouth of the blast furnace can be of more compact construction overall.
Guiding the flap plate along the arcuate paths brings about, in the region of the opening, a relative movement between the rim region of the flap plate and the sealing seat provided for the flap plate at the bottom opening. Especially when the sealing region of the flap plate is in contact with the sealing seat of the bottom opening, a relative movement parallel to the plane of the opening is damaging and can result in premature wear of the sealing provisions.